Technique to model a 3D button (Image attached)
Here's the Text version of the Step-by-Step (please see Images below for visual reference of each step).


In Object Mode add a plane by hitting: Shift+A -> Plane.
Hit TAB to enter into Edit Mode.
Select all Vertices by hitting A. Hit Delete -> Only Faces.
Select all Vertices by hitting A. (**NOTE: Repeat the Next Steps 3 Times) Hit W -> S.
Add a circle mesh by hitting Shift+A -> Circle. Next scale it down by hitting S -> 0 -> . -> 5 -> Enter.





Ensure all Vertices are selected (A to toggle - you will probably have to hit this twice at this point), then hit W -> E, this will invoke the Bridge Edge Loops command to fill the gap between the rectangular mesh perimeter, and the inner circular mesh perimeter.





Hover your cursor over one of the newly created connection edges (eg. about the mid-point on an edge that spans from the perimeter plane to the perimeter circle) and hit Ctrl+R. Next move your mouse until you have the desired shape, then Left Mouse Click.




Refer to 

 

for how to manipulate it afterwards.